Electromagnetic operator



June 17, 1947. w. A. RAY

ELECTROMAGNETIC OPERATOR Original Fil ed Nov. 25, 1942 I'mventor: W/zMAM A. Pny,

(Zltorneg.

Patented June 17, 1947 2,422,260 ELECTROMAGNETIC OPERATOR William A.Ray, Los Angeles, Calif., assignor fir General Controls 00., acorporation Original application November 23, 1942, Serial No.

1945, Serial No. 606,345

4 Claims.

This invention relates to low energy-consumption electromagneticoperators, and more particularly to those of the iron-cladsingle-workinggap type; the present application being a division of mycopending application Serial No. 466,636, filed November 23, 1942; nowPatent No. 2,382,664, granted August 14, 1945.

In Patent No. 2,358,828, granted to me September 26, 1944, I disclose.an electromagnetic operator, of the series working-gap type, the energyconsumption of which is very small in comparison with that ofelectromagnetic operators of conventional form and capable of performingequivalent work; the improvement residing mainly in the provision of acore having, at its ends, enlargements forming pole-faces which areconsiderably greater in area than the cross-sectional area of the bodyof the core. The improved operation of that device is mainly due to thefact that, when the fiux density in the core (produced by a. weakmagnetizing force) is at a point considerably below the knee of themagnetization curve for the core material, the flux density in thelarge-area pole face is substantially the same as that which could beproduced by the weak magnetizing force if the cross-sectional area ofthe body were not reduced; reduction of the body area making possiblethe use of a coil winding of small mean turn diameter andcorrespondingly small electrical resistance. It is a general object ofthe present invention to apply similar principles to provide a lowenergyconsumption electromagnetic operator of the single working-gaptype.

A more specific object of the invention is to provide an iron-cladelectromagnetic operator having a plunger-type armature and embodyingthe principles set forth hereinabove.

Another object is to provide an electromagnetic operator, of thecharacter described in the preceding object, which is especially adaptedfor energization by a pair of separate coil windings.

For full understanding of the invention, and further appreciation of itsobjects and advantages, reference is to be had to the following detaileddescription and accompanying drawing, and to the appended claims.

In the drawing, the single figure of which is a longitudinal sectionalview of an electromagnetic operator embodying the invention, thenumerals 3i and 32 indicate a pair of cup-shaped core portions which areintimately joined together by tightly lapping the mouth of one over thatof the other, screws 33 serving to secure the Junction. Attached, as bywelding, to the Divided and this application July 21,

end wallof the upper core portion 31 is a cylindrical inner core portion34 having at its free end a cylindricalstop or head 35, of the samematerial as the core portion, the underside 33 of which forms the poleface of the electromagnet. Welded in a central opening through the endwall of the lower cup-shaped portion 32, and so arranged that it extendsto a considerable distance from either side of the wall, is a sleeve 31of magnetic material. A press-fit within this sleeve is another sleeve38, of thin non-magnetic material, having at its inner or upper end,immediately above the corresponding end of the outer sleeve, a flange33. A sliding fit within the inner sleeve is a magnetic plunger '46, theouter end of which is adapted to be connected to a, device to beoperated. The plunger has at its upper end a cylindrical head 4|, alsoof magnetic material, the top surface of which defines with the poleface 36 the working-gap of the electromagnet. Direct engagement of theheads 35 and 4|, when the electromagnet is energized, is prevented by anon-magnetic button 42 set in he lower head; and, when the plunger is inits unattracted position as shown, the underside of its head isseparated from the magnetic sleeve 31 by the non-magnetic flange 33. Theadjacent surface areas of the heads 35 and H are several times greaterthan the cross-sectional areas of the core portion 34 and plunger 40,respectively, but the heads are preferably of such diameter that thespace between them and the outer core portions is large enough toprevent material lateral leakage of flux. For energizing theelectromagnet, a pair of coil windings l3 and 44, connected in aidingrelation and having external leads 45, are provided; one windingsurrounding the core portion 34 and the other the magnetic sleeve 31.Due to the large surface area of the sleeve 31 adjacent the plunger 40,the reluctance of the fixed air-gap between these parts is relativelylow. To increase the flux-conducting capacity of the end walls of theouter core portions 3| and 32, disks 46 and 41, of magnetic material,are welded to their outer surfaces.

The embodiment of my invention herein shown and described is susceptibleof modification without departing from the spirit of the invention,

and I intend therefore to be limited only by the scope of the appendedclaims.

I claim as my invention:

1. In an electromagnetic operator of the single for an energizing coilwinding; said inner core portion being relatively small in cross-sectionand having at its free end a disk-like head providing a substantiallyplane pole face the area of which is at least several times greater thanthe crosssectional area of the small part of the inner core portion; aplunger-lik armature substantially coaxial with said inner core portionand extending through an opening in a wall of said outer core portion,said armature having at its inner end a disk-like head providing asurface substantially coextensive with that of said pole face anddefining therewith a working-gap; said outer core portion providing atsaid opening an inward extension surrounding the plunger portion of thearmature and in good flux-transfer relation thereto; a coil windingsurrounding said small part of the inner core portion; and an additionalcoil winding surrounding said inward extension of the outer coreportion.

2. In an electromagnetic operator'of the single working-gap type: a coremember comprising a hollow outer portion formed by side walls and a pairof opposite end walls, and an inner portion extending from one of saidend walls to define with said side walls a space for an energizing coilwinding; said inner core portion being relatively small in cross-sectionand having at its free end a disk-like head providing a substantiallyplane pole face the area of which is at least several times greater thanthe cross-sectional area of the small part of the inner core portion;the other face and defining therewith a working-gap; a 4

col] winding surrounding said small part or the inner core portion; andan additional coil winding surrounding said sleeve.

0 Number 3. An electromagnetic operator, as defined in claim 2,including a sleeve of thin non-magnetic material interposed between saidmagnetic sleeve and the plunger portion of said armatur and extendingbeyond the inner end of the magnetic sleeve so as to prevent directengagement of said armature-head with the magnetic sleeve.

' 4. In an electromagnetic operator oi the single working-gap type: acore member comprising a pair of cup-shaped portions lOined together attheir mouths, and an inner core portion extending from the inner surfaceof the end wall of one of said clip-shaped portions in spaced relationto the side walls thereof; said inner core portion being relativelysmall in cross-section and having at its free end a disk-like headproviding a substantially plane pole face the area'of which is at leastseveral times greater than the cross-sectional area of the small part ofthe inner core portion; the end wall of the other of thecupshapedportions having an opening therethrough on the axis '01 saidinner core portion; a sleeve of magnetic material joined to saidlast-mentioned end wall and extending inwardly from said opening alongsaid axis; a plunger-like armature slidable in said sleeve and having atits inner end a disk-like head providing a surface substantiallycoextensive with that of said pole fac and defining therewith aworking-gap; a coil winding surrounding said small part of the innercore portion; and an additional coil winding surrounding said sleeve.

WILLIAM A. RAY.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Name Date 1,333,542 Geissinger Mar, 9, 1920

